Photochemistry
PQ and water oxy-trifluoromethylate enynes
Open access · cc by · source: Europe PMC
Sunlight-excited phenanthrenequinone turns Langlois’ CF3SO2Na into CF3· and uses water as the oxygen atom to build CF3 benzofurans, benzothiophenes and indoles.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
CV also appears as a supporting characterisation of materials and mechanisms: pore-confined Pt–Ni ORR, a stibnite/carbon sodium-ion composite, and a photoredox trifluoromethylation where CV of 9,10-phenanthrenequinone sits beside EPR and ¹⁸O labelling. Those papers are not primarily about teaching CV, but they still use a voltammogram as evidence.
Evidence for the claim as stated.
Study at a glance
- Design
- Animal / in-vitro — Phenanthrenequinone photoredox cascade on 1,6-enynes with 18O-water, EPR, and DFT
- N
- Substrate-scope benzofurans, benzothiophenes, and indoles rather than a single N
- Population
- Phenolic 1,6-enynes with Langlois’ CF3SO2Na and water
- Outcome
- Visible-light, metal-free cascade trifluoromethylates and oxidizes 1,6-enynes, with water supplying the ketone oxygen
Structured fields used in claim comparison tables when every cited study has a complete layer.
Inspect source passages
PQ and water oxy-trifluoromethylate enynes
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Electron-diverse phenolic enynes give trifluoromethylated benzofurans in 57–75% yields.
Substrates 1b–1j , with electron donating as well as electron withdrawing substituents on the ethynyl ring, showed compatibility with the optimized reaction conditions and afforded respective trifluoromethylated benzofurans 2b–2j in 57–75% yields ().
The photocatalytic quantum yield is φ = 27.
The determined QY is φ = 27 (for details, see the ESI page S17) which suggests that 27 equivalents of product 2a are formed for every photon absorbed by the photocatalyst PQ .
Key findings
PQ in CH3CN/water under sunlight (or 23 W CFL) gives benzofurans 57–75%, benzothiophenes 73–36%, N-Ts indoles 67–56%. 18O lands in the ketone (m/z 307.0821). H2 (δ 4.57 ppm) and H–D from D2O evolve. EPR sextet of tBu(CF3)NO·; φ = 27 implies a chain. DFT hydration barrier +16.47 kcal mol–1.
Methodology
Authors screened diketones/oxidants on phenolic 1,6-enynes, then mapped O-, S- and N-linked substrates, 18O-water labelling, EPR spin trapping, CV of PQ, and B3LYP hydration barriers.
Limitations
Alkyl-substituted enynes give low yields; Boc-indoles can drop to 10%; H2 is inferred from NMR not quantified gas chromatography; chain carrier HSO2· is proposed, not isolated.
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